[pianotech] Increasing bridge height

[Will Truitt]

Hi Ron:

" Mine too, and since the string height is likely 5mm lower in 
the upper treble anyway, that works out fine."

I am guessing that what you are saying her is that your practice of raising
the bridge is essentially the same as Del's, but I am not sure what you are
trying to say about the string plane in the upper treble (although I know
that the string height tapers down as you progress into the treble in
Steinways, if that is what you are referring to).  I don't know what you are
referring to with "works out fine".  Please explain a bit more fully.

My stack is slightly out of level.  The whippen center pins are at the same
height on 1 and 88, but the hammer shank center pins are about 1.5 mm higher
at 88 than 1.  Not sure how I will address that yet, I was just taking
measurements today.  But that won't change much anyway.  

I take your comments about the stack and bore to mean that you are boring
the tenor and treble hammers to one measurement, albeit one that reflects
the 4 or 5 mm higher string height, yes?

Thanks for your comments.

Will 


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Monday, March 23, 2009 7:27 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Increasing bridge height

Will Truitt wrote:
> The bridge height at note 88 is about 25.5 mm, about 28
> around note 70, 30 at note 40, and 33 just below note 21 (it's a 20 note
> bass piano). Del's practice is to take 88 up to at least 30 mm.

Mine too, and since the string height is likely 5mm lower in 
the upper treble anyway, that works out fine.


> There are some things associated with making the change of the plate
> elevation that must accompany the taller bridge that I want to have a
better
> sense of.  One, the higher string plane will likely necessitate the use of
> new damper wire, as the old may be too short, yes?  

Maybe, but most likely not.


> The other concern that I have is the need for a longer hammer bore that
must
> accompany the change to the string plane height. Not the boring or
> calculating of the measure - I've been doing that for over 20 years - but
> rather the low entrance into the action cavity that Steinways have at the
> bottom of the stretcher.  As you know, there is often scant clearance for
> the hammer drop screws, which leaves little room to raise the action stack
> if that becomes part of the overall equation.  

Look at that before you decide. I typically find that the 
stack is level and with the high treble string height closer 
to that in the tenor, boring all the tenor and treble hammers 
the same length makes it a lot closer to right than it was 
originally. No stretcher clearance issues. But check all that 
first before committing.

Ron N